Thermionic or oscillation valve



May 13 1924. 1,493,696

s. R. MULLARD THERMIONIC OR OSCILLATION VALVE Filed Nov. 9, 1920 323 of examp atented av mm STATES PATENT ounce.

STANLEY ROBERT MULLARD, F SOU'IHFIELDS, ENGIAND, ASSIGNOB TO THE MULLABD RADIO VALVE COMP, LIMIEEED, 0F SOUTHFIELDS, LONDON, ENGLAND.

TMIONIC 0R OSCILLATION VALVE.

Application filed November 9, 1920. Serial No. 422,980. I

- Southfields, in the county of London, England, have invented certain new and useful Improvements invor Relating to Thermionic or Oscillation Valves, of which the following is a specification.

w This invention relates to thermionic or osclllatlon valves of the kind in which the bulb has a reentrant portion for supporting an electrode. -The invention is particularly applicable to valves having glass bulbs but 15 it may also be applied to valves having bulbs of fused silica. The chief object of the invention is to provide improved forms of valve which permit of replacement of the electrodes and especially of the heating filament. Another object of the invention is to provide improved means for supporting the electrodes and insulating them from each other.

According to one feature of this invention in a valve of the kind referred to a sealing tube is attached to the reentrant portion of the bulb and extends outwards beyond the general contour of the bulb to permit of rescaling.

2t In order that-the above and other features of the invention ma be clearly understood and readil carried into efiect the same will now be fu y described with reference to the accompan ing drawings which show by way h s methods of carrying the invention into effect and in which Figure 1 is a view partly in section of one i form of valve according to this invention,

Figures 2 and 3 are sections on an enen larged scale on the lines 2-2 and 33 respectively in Figure 1,

Figures 4 and 5 are details,

Figure 6 is a view showing part of a valve according to another method of carryinthe invention into efiect.

eferrin to Figures 1 to 5, the valve comprises a bu b 1 having tubular necks 2and 3. Within the necks 2 and 3 are reentrant parts 4 and 5 to whichare sealed at 6 and 7 at tubes 8 and 9 which extend outwards well beyond the bulb 1 and'necks 2 and 3. To the outer end 10 of the tube'8 a tube 11 is sealed. Sealed into the innerend of the tube 11 areconductors 12, 12 to the inner ends of which the filament 14 is connected. The leads 15,. 15 for the filament pass through the tube 11. At the other end of the valve a tube 16 is sealed at 17 within the tube 9. The inner closedend of the tube 16 is formed with a solid knob 18. A wire spring 19 is formed with a hooked end 20 over which the filament 14 passes and the other end of the wire is bound around the neck 21 behind the knob 18.

The grid is formed by a wire spiral wound on three supporting wires 31 which latter are rigidly attached to three arms 32 extending from a piece of metal 33 bent into cylindrical form (Figures 1 and 4);

The part 33 is inserted within the tube 11 fitting the same tightly. Connection is made to the grid by a wire 34.

The plate electrode (Figures 1 and 5) is in the form of a cylinder attached to three arms 41 extending from a part 42 (similar to the part 33 hereinbefore desclibed) and fitting tightly within the tu e 9.

- It will be seen that the construction of faces are provided between the filament and the 'd and between the filament or supporting means therefor and the plate elec% trode.

The invention is applicable to valves in which a sealing tube is sealed at its inner 1 end to a reentrant portion. Such an arrangement is shown in Figure 6 in which the tube issealed to a reentrant tube 51 at 52. A conductor 53 connecting to a filament is sealed in the tube 50 which extends well beyond the body of the valve. The filament -may be a straight one extending across the bulb.

The late or grid electrode may be supported y arms 54 attached to a band of metal 55 surrounding the reentrant tube 51.

The invention is obviously applicable to valves having only twoelectrodes or more reeemoe than three electrodes. The electrodes may also obviously be of other forms than those specially described above. 7

What I claim and desire tosecure by Letters Patent of the United States is:

1. A thermionic electric valve of the kind in which the bulb is provided with a reentrant portion for supporting an electrode and in which a sealing tube is attached to the said reentrant portion and extends out- Wards beyond the mouth of said reentrant portion for the purposes described.

2. A thermionic electric valve of the kind in which the bulb is provided with a reentrant portion for supporting a sealing tube carryin the filament and in which the said seahng tube extends outwards beyond the mouth of said reentrant portion for the purposes described.

3. A thermionic electric valve comprising a bulb having a reentrant tubular portion, a tubular portion Within said first mentioned tubular portion and attached to the inner end thereof and: a sealing tube carrying the filament attached to the outer mouth of said first mentioned tubular porf tion.

5. A thermionic electric valve comprising a bulb having a tubular reentrant portion, a tubular part within it joined to the inner end of said reentrant portion, a sealing tube attached to the outer end of said tu ular part and an electrode supporting member comprising a cylindrical part adapted to fit tightly Within said tubular part between it and] the sealing tube and having a plurality of arms extending therefrom to the outer ends of which the elec trode is attached.

STANLEY ROBERT MULLARD. 

